This invention concerns evaporative cooling towers, fluid coolers and evaporative condensers, and specifically the amelioration of the air and spray water flow within the evaporative cooling equipment. This invention improves air distribution while reducing airflow resistance to increase the thermal capacity for a given footprint of the evaporative cooling tower. In addition, this invention seeks to provide self-cleaning, easy to access, inspect and maintain evaporative cooling equipment.
The improvement in airflow distribution, and decrease in airflow resistance, is achieved by reducing the amount of obstruction and turns in the airflow path, and by opening the plenum area around the fan. Typical forced draft evaporative cooling equipment with side inlet fans have uneven airflow distribution to the heat exchanger arranged above the fan. Solid baffles or fan housings are typically arranged to shield the mechanical and fan components from the falling water droplets through the heat exchanger. Given the near perpendicular arrangement of the entering air velocity provided by the fan, the turning losses to the heat exchanger contribute significantly to the total static pressure acting against the fan and increased fan energy consumption for a given airflow. For forced draft evaporative cooling equipment using an unhoused fan, the fans and fan plenum are separated from the heat exchanger for water management concerns, and are not positioned directly under the heat exchanger section, resulting in poor fan performance due to higher airflow resistance, large unit footprint and higher unit cost due to the side-by-side heat exchanger and fan sections.
In this invention, improved overlapping gutter water collection systems are introduced to improve airflow distribution, decrease airflow resistance and improve the water collection system design. A new embodiment has the spray water pump being mounted above the forced draft fan(s) and another new embodiment includes integral air activated dampers which open when the fan(s) is on and close when the fan(s) is off thus stopping natural airflow when the fan is off and prevents any water droplets from exiting the water collection system when the fan is off.
The overlapping gutter water collection systems are designed to collect the spray water flowing from the top side, while letting air flow generally vertically through from the bottom side. The system is made of single-piece gutter assemblies stacked side by side and overlapping. In some embodiments presented, the water collection system may cover only part of the footprint of the unit which allows for fine balancing of the airflow resistance and greater control of the airflow paths through the units. When covering only part of the unit footprint, and by being sloped, the water collection systems create a water cascade from the water collection channels to the sump. The cascading water is mixed with air passing through which becomes an extended rain zone, which allows for additional cooling of the spray water resulting in higher unit thermal performance. Other embodiments presented have the complete footprint of the unit covered by the overlapping gutter water collection systems.
One improvement of the invention presented is that the sloped overlapping water gutter collection system assemblies are composed of two water collection channels: a primary water collection channel that collects most of the spray water, and a secondary water collection channel that collects the remaining spray water. Another embodiment introduces even a tertiary water collection channel. All of the channels are made wide enough to prevent clogging due to debris and other factors, and to be easily inspected and cleaned, as needed. The air passages of the gutter assemblies are designed to minimize airside pressure drop while improving water collection performance. Drip edges are added to improve water catching performance, as necessary. If water splash out is a concern, a water collection trough can be incorporated in the design, at the discharge side of the water collection channels of the gutter system. The spray water is collected in the trough, and can drain to the sump via a pipe, under the action of gravity, reducing the amount of water splashing in the sump. In addition, louvers can be added under the water collection system to isolate the sump area from the fan area. If high water collection capacities are required, a design with three integrated water collection channels can be used. The gutter assemblies could be parallel or perpendicular to the direction of the air intake, depending on the needs of the application. In some embodiments, overlapping water gutter collection systems can also act as water silencers by catching most or some of the spray, shortening the waterfall distance from the heat exchanger to the sump. In some embodiments, when the fans are operating, the water falling from the gutter assembly which collects a portion of the evaporative liquid, usually water, is forced to back side wall. In operation this reduces splashing potential, cleans the back side wall and reduces splashing water noise. In some embodiments the sump is located within the outside structure of the cooling tower. In other embodiments the sump can be located remotely from the cooling tower or the sump is mounted externally to the outside of the cooling tower.
The hygiene, self-cleaning, easy to access, easy to inspect and easy to maintain aspects of this invention are realized by the overlapping gutters protecting mechanical components from falling water from the heat exchanger, allowing dry internal access between the sump and fan for inspection and maintenance. In addition, overlapping gutters are at an angle, typically greater than 0° and less than 80°, where 0° refers to a horizontal plane, with optimal angle between 1° and 5°, to increase water velocity and drainage, resulting in a self-cleaning system. The slope also results, in some embodiments, in water cascading in the sump. This high velocity water stream can increase water movement in the sump, thus reducing the risk of biological growth from stagnant sump areas. In addition, a cleaning system could be integrated to the water collection gutter designed, providing a pressurized and gravity driven water stream to flush out the water collection channels. Finally, keeping the spray water as far away from the air intake as possible greatly reduces to risk of water splashing out through the fan, and the risk of freezing in the winter, especially when the fans are not in operation.
For most embodiments presented, evaporative cooling equipment is in forced draft, single-singled air inlet configuration, but it is not a limitation of the invention, and of the embodiments presented. The invention also concerns double-sided air inlet, triple-sided air inlet, and quadruple-sided air inlet forced draft evaporative cooling equipment, as well as single-sided air inlet, double-sided air inlet, triple-sided air inlet, and quadruple-sided air inlet induced draft evaporative cooling equipment.